• Ou (歐) is pronounced as "ōu" in Mandarin Chinese, with a rising tone.
• Yang (陽) is pronounced as "yáng" in Mandarin Chinese, with a rising tone.
• Chen (晨) is pronounced as "chén" in Mandarin Chinese, with a rising tone.
• Xi (曦) is pronounced as "xī" in Mandarin Chinese, with a rising tone.

So, the full name "Ou Yang Chen Xi" (歐陽晨曦) is pronounced as "ōu yáng chén xī" in Mandarin Chinese.